Motion picture apparatus



May 5, 1931. H, HOFFMAN ET AL 1,804,340

MOTION PICTURE APPARATUS y Filed sept. 1o, 1928 4 sheets-sheet 1 May 5, 1931. l H. HOFFMAN ET AL. 1,804,340

MOTION PICTURE APPARATUS May 5, 1931. H. HoFFMAN ET AL MOTION PICTURE APPARATUS Filed Sept. l0, 1928 4 Sheets-Sheet 3 Cy Zglf Hfafffay www 1* www May 5, 1931.

H, HOFFMAN ET AL MOTION PICTURE APPARATUS Filed Sept.`

1928 4 Sheets-Sheet 4 zza @AMK

Patented lllay E, lQSl rennt uren stares natur orales RY HOFFMAN', 0F PHILDELBBIA, AND PAULF- KABST, OF HIGHLAND PARK,-

EEdSYLVAll., ASSIGNORS GF SNE-THIRD TO LOUIS HOFFMAN, E PHILADEL- PEENSYLVARIA.

morren riorunn v.enrnnnfrus Application lc; September 10, 1928. Seriali No. 3M,93U

@ur invention relates to motion picture ma@ chines, and it has for one object theprovision of simple and efiicient safety means, whereby the motion pictureV mechanism may be rene dered inedective upon the occurrence of predetermined operating conditions.

lnother object oi our invention is to provide a motion picture machine, wherein not only is the dowser operated upon the occurrence oi a predetermined undesirable condition but the light is also extinguished and the driving motor is deenergized.

A further object of our invention is to provide, in apparatus of the character described, a step-down transformer, whereby the problem oi; insulation may be reduced to a. minimum.

A still inrther object of our invention is to provide a motion picture machine that shall comprise means for establishing a light beam, a hlm, a dowser for intercepting the light beam provided with electrical trip mechanism, driving mechanism for the film and associated movable parts, a switch responsive to an abnormal operating condition of at least one of said parts, a normally closed circuit including the switch and the electrical trip mechanismT and means whereby the lightv may be extinguished upon the operation oi the switch.

@ther objects and application of our invention, as well as detailsv of construction, operation and circuit arrangement, whereby our invention may be practiced, will be apparent more fully hereinafter, when taken in connection with the acompanying'drawingss wherein Fig, l is a side elevational view of a Inoving picture machine embodying our invention, a portion of the projecting machine housing and associated parts being removed;

Figs* 2 and 3 are. side and end elevational views, respectively, of a dowser embodying our invention;

Fig. l is a horizontal sectional vieur taken on the line oi Fig. 3i;

Figs. and 6 are top plan and side elev `tional views of one of the control switches s own in Fig. i, the switch-housing being shown in horizontal section in Fig.

Fig. 7 is a transverse sectional view taken 'on the line VII-VH of Fig. 6; and

Fig. 8 is a diagrammatic view of circuits ing 5 which receives a ihn 6' from an upperV hlm reel 7 and discharges said hlm on. to a lower rewinding reel 8; driving mechanism 9 including an electric motor ll, whereby sald film may he moved through said housing so as to pass' over a light aperture l2 positioned in alignment with the lens heus' ing 3; a dowser i3 having an electromagnetically controlled trip mechanism lll permitting the light beam established by the arc electrodes 2. to be intercepted upon the occurrence of a certain condition; switch apparatus l5 which is responsive to abnormal operating conditionsA in the moving parts of the motion picture machine; and a normally closed electrical system 16 (Fig. 8), which includes theV switching apparatus 15, the trip mechanism I4, the driving motor 1l and the arc electrodes-2,A whereby the dowser 13 may be actuated into its light intercepting position, the light beam. formed by the electrodes 2 extinguished and the motor l1 deenergized upon the actuation of the switching apparatus l5 due to an abnormal operating condition in at least one of the movable parts oi the motion picture machine, all as will ap pear morev fully hereinafter.

Reerring to the driving mechanism 9 in greater detail, the driving motor l1, which. is mounted on a pedestal 17 having a main supporting platform lilV for the lamp housing l, the dowser i3 and the projecting machine housing 5 and associated parts, is connected by a belt i9 with a main driving pulley-wheel 2l which has been shown in dot-and-dash lines The portion. ofy the belt 19 immediately adjacent to the pulley-Wheel 2l is also shown in dot-and'dash lines inasmuch as these parts have been removed by reason. oi

the location of the vertical sectional plane through the projecting machine. A lower half 22 of the belt 19 passes over a loose pulley wheel 23 while an upper half 24 passes over a loose pulley-wheel 25. The lower iilm magazine or reel 8 is rotatably mounted on a shaft 26 carrying a pulleywheel 27 over which passes a belt 28 extending from a pulley-wheel 29 having a connection (not shown) with themain driving pulley-wheel 21.

The film 6 passes from the upper film magazine or reel 7 downwardly intopthe housing 5 around a sprocket-wheel 31 and associated bearing roll 32, then upwardly and downwardly so as to form a ilm loop 33 just above the light aperture 12. After passing over the light aperture 12, the iilm passes between av sprocket-wheel 34 and co-acting bearing roll 35, so that a positive movement of the film 6 over the light aperture 12 may be further assured. The fllm is now curved backwardly on itself to form a lower loop 36 which extends in the direction of the dowser 13. From here, the lm 6 'passes between additional driving parts comprising a sprocket-wheel 37 and co-acting bearing wheel 38, finally leaving the housing 5v and passing vonto the rewinding reel \8. `The sprocket-wheels 31, 34 and 37 are actuated by mechanism (notshown) driven by the main pulley-wheel 21 and comprise parts of the driving mechanism 9.

ln accordance with our invention, theV switching apparatus 15 functions to prevent the further operation of the motion picture machine upon the occurrence of abnormal operating conditions. rl`his apparatus includes switches 38, 39, 41 and 42 which are positioned as shown in Fig. 1. Each switch may comprise a stationary, spring contact member or element 43 and a co-acting movable contact member or element 44, as illustrated in Figs. 5 to 7, inclusive. rlhe stationary contact member 43 is mounted on an inner wall 45 of one side 46 of an angle frame 47 consisting of an insulating material. Another slde 48 of the frame 47 serves as a support for an outwardly extending bolt 49 upon which is positioned an insulating sleeve 51. An inner end of the sleeve 51 loosely engages a washer 52 abutting'against a nut 53 which is mounted on a threaded portion 54 of the bolt 49. The sleeve 51 is prevented from moving beyond the outer end of the bolt 49 by means of a nut 55 and a washer 56. The spacing between the washers 52 and 56 is such that the sleeve 51 may turn loosely. The movable contact member 44 of the switch is mounted on an arm 57, one end 58 of which encircles the sleeve 51 and is secured thereto by means of a setscrew 59.

A strap member 61 is adjustably secured on the outer end of thel sleeve 514by means of incase@ a set-screw 62 and it provides a mounting for an elongated rod or arm 63, an outer end 64 of which is transversely bent and adapted to provide a support for a'film spool 65 or a belt pulley-wheel 66 as shown in Fig. 1. The film spool 65 or the belt pulley-wheel 66 may be resiliently held in engagement with the film 6 or one of the several belts by means of a spring 67 which extends from' a clamping screw 68 to an adjacent fixed support. Certain of the switch parts may be enclosed by a protective casing comprising a side "wallv 69, which is positioned between the switch arm 57 and the strap 61, an end wall 71, and top and bottom side walls 72 and 73, as illustrated in Figs. 5 to 7, inclusive. e

rlhe switch 38 is preferably positioned in an upper portion of the projecting machine housing 5 with its arm 63 extending upwardly, so that the lilm spool 65 engages lthe film loop 33'. The spring 67 establishes a resilient engagement at this point and is of sucient torce to cause the upward move.- ment of the arm 63 in the event that the film loop 33 should break. rlhe relation between the switch arm 63 and the contact elements 43 and 44 is such that, so long as normal conditions obtain as shown in F ig. 1, these contact elements are in engagement and the switch 38 is therefore closed. llilowever,`

downwardly into the end of the loop 36. So

long as normal conditions obtain, the relation vbetween the switch arm 63 and the `Contact members 43 an-d 44 of this switch are such that these elements are in engagement, but should the loop 36 break, then the arm 63ismoved downwardly under the force of the spring v67 and disengagement occurs. rl"he switch 39'is also opened in the event that the arm 63 moves upwardly by reason of a decrease in the dimensions ofthe loop 36.

Theswitch 41 is mounted on an underside 75 of the supporting platform 18. The switch arm 63 extends downwardly and the belt pulley-wheel 66 thereof is held in engagement with a portion 76 of the rewinding reel belt 28 by means of the spring 67. rlhe release of these parts is such that so long as the normal conditions shown in Fig. l are continued, the switch contact elements 43 and 44 are in engagement. ,Howeven -should the belt 28 break and abnormal slack occur therein, the

arm 63 is actuated under the force of the.

spring 67 suciently to disengage the contact elements 43 and 44 and hence open the switch 41.

The switch 42 is similarly positioned on the underside of the platform 18, but the pulleyfwheel 66 is in engagement with the side portion 22 of the'motor belt. The relation of these switch parts is such that disengagement of the contact elements 43 and 44 occurs only when an abnormal amount of slack is present in the motor belt 19 or when said belt breaks. The switches 38, 39, 41 and 42 and the motor 11 are serially connected in a normally closed circuit 77, as shown in Fig. 8. The switch circuit 77 is preferably a socalled low-voltage circuit, so that vthe problem of insulation may be reduced to a minimum. To this end, we provide a step-down transformer 78, a secondary winding 79 of which is included in the circuit 77, while a primary winding 81 is connected to terminals 82 and 83 of the usual alternatingcurrent lighting circuit 84. Plug fuses 131 and 132 are provided between the terminals 82 and 83 and the terminals leading to the motor circuit and the transformer 78. These fuses are provided to break the supply circuit in the event that an over-load occurs on the line 84. When either of these fuses is blown, it simultaneously opens the motor circuit through line 121, contact 119 and line 117. At the same time, the primary 81` of transformer 78 is opened and the secondary 79 rendered inellective, whereby the winding 125v of relay 129 is deenergized and the armature 124 caused to open the circuit ot relay 122 and the spring 130 pulls the multiple switch 111 from the contacts 119, 112 and 113. The breaking of the contacts 112 and 113 opens the arc circuit 106 and 107 and thereby extinguishes the arc 2.

Our invention further contemplates means whereby the light beam passing between the lamp house 1 and the light aperture 12 of the housing 5 may be intercepted upon the occurrence of abnormal operating conditions. Accordingly, we provide the dowser 13 and its associated electromagnetic trip mechanism 14, ot which Figs. 2 and 3 are side elevational views and Fig. 4 is a horizontal sectional view, taken on the line IV-IV- of Fig. 3. As therein shown, this structure comprises a standard 85 having a base portion 86 and an upright portion 87. An upper end of the upright portion 85 is provided with spacedarms 88. Upper ends of the spaced arms 88 support a shaft 89 upon which is mounted an angle member 91. A side 92 of the member 91 entends normally downwardly and it is provided with an opening 93 through which the light beam may pass. Another side 94 of the angle member 91 is horizontally positioned so as to not interfere normally with the light beam. The side 94, however, is considerably heavier than the vertical side 92, whereby it may tend to move into the 'dot-and-dash line position shown in Fig. 3 wherein the light beam is intercepted.

The tendency for the imperforate side 94 to move into its light-intercepting position is prevented by the electromagnetic trip mechanism 14 so long as desired operating conditions are maintained. The trip mechanism 14 comprises a vertically movable trip rod 95,

an upper end 96 of which engages a shoulder 103 which is supported by a bracket arm- 104 extending from the upright standard portion 87. A spring 105 is positioned between the arm 104 and the armature 99 and it has suflicient force to actuate the rod 95 positively downwardly when the electromagnet 98 is dcenergized due to the operation of the switch apparatus 15, as will presently appear. Such movement causes the end 96 of the trip rod 95 to disengage the shoulder 97, thereby permitting the inperforate side 94 of the angle member 91 to drop under its own weight into the light-intercepting position shown in dotand-dash lines in Fig. 3.

As shown in Fig. 8, the electromagnet 98 is connected in the secondary circuit 77 in seriescircuit relation with the control switches 38, 39, 41 and 42. Hence, the operation of any one of these switches causes the opening of the safety circuit 77, the consequent deenergization of the electromagnet 98 and the actuation o'f the tripping mechanism 14 by the spring so as to permit the angle member 91 of the dowser to move into its light-intercepting position. rlhe beam of light is thus preventedfrom heating the film 6 to the burning point upon the occurrence of abnormal conditions.

A still further important feature of our invention is the extinguishment of the light beam when predetermined abnormal operating conditions occur, such, for example, as the inoperation of one of the belts or the driving motor 11 or the breakage of the film 6. In accordance with our invention, this desired result is eilected in the manner shown in Fig. 8 wherein the arc electrodes 2 are connected by conductors 106 and 107 to movable contact members 108 and 109 respectively of an electro-magnet switch or relay 111. A pair of stationary contact members 112 and 113, which co-act respectively with the movable contact members 108 and 109, are connected by conductors 114 and `115 to a source of direct-current energy (not shown). The

electro-magnet switch 111 also includes ya.

lll() lli third movable contact memberll which is connected by a conductor 117 to one-terminal of the driving motor 11, an opposite terminal being connected by a conductor 118 to the terminal connection 83. The movable contact member 116 co-acts with a stationary contact member 119 which is connected by a conductor 121 to the other terminal connec tion 82. Y

An actuating winding 122 of the electromagnet switch 111 is connected by a conductor 123 to a movable switch element 124 of a relay 125, the element 124 normally engag- -ing a co-acting stationary contact element 126 which is connected by a conductor 127 to one terminal of an alternating-current source of energy (not shown). An opposite terminal of this source is connected through a snap switch 128, which is preferably positioned immediately adjacent to the moving picture machine, to the remaining terminal of the actuating winding 122 of the electro-magnetic switch`111. 'lhe relay 125 has an actuating winding 129 connected in series-circuit relation with the switch apparatus `and electromagnet 98. y

Assuming the parts in the positions-shown in the drawings, wherein the switch-es 111 and 124-126 and 128 are closed, the projecting machine operates in the normal manner. 1t is noted that direct-current energy is supplied tothe arc electrodes 2 so as to establish the beam ot light; that the electromagnet 98 is energized, thereby causing the dowser member 91 to be held in its ineffective position;

and that the motor 11 is supplied with alternating currents, causing the operation of the 'l driving mechanism`9 and the resulting movel the tripping mechanism 14 ment of the film 6 and associated movable parts. However, shouldv the' low-voltage circuit 77 be interrupted by reason of the opening of one of the switches 38, 39, 41 and 42 due to undesirable operatin' conditions, then ctions to cause the dowser member 91 to move into its lightintercepting position. A

Since the relay 125 is now de-energized, the

' contact members 124'and 126 separate, causing the de-energization of' the electromagnetic contactor 111. A spring 130 of the contactor 111 now actuates the movable switch members 108, 109,V and 116 out of engagement with their stationary contact members 112, 113 and 119, resulting in the de-energization of the driving motor 11 and an interrup` tion in the supply of'energy to thev arc elec trodes\ 2. The light beam is thus extinguished land the driving motor 11 rendered ineffective. The snap switch 128 should now be actuated 'into'jits open position so as to j prevent the premature operation ofthe' motion picture machine following the correction of the abnormal'cbdition andthe rc-setting 'of the switchy mechanism 15v and trip mechaj Bisel# While we have shown only one emboent of our invention, tor the purpose of -describing the same and illustrating its principles of construction and operation, it is apparent that various changes and modifications may be made 4therein without departing from the' spirit of our invention and we desire; therefore, that only such limitations shall be imposed thereon, as are indicated in the appended claims or as are demanded by the prior art.

We claim:

1. ln combination, means for establishing ya beam of light, a film positioned in operative relation to said light beam, operating mechanism for said film including a driving motor and connecting belts, switches res ctively positioned in such relation to said elt and said iilm as to be operated upon the occurrence of predetermined conditions, a normotor, and means for causing the extinguishment of said light beam and opening of the .motor circuit upon the operation of at least- 'as mally closed circuit including said driving 3f. 1n combination, means for forming a light beam, a film positioned in operative relation to said light beam, a dowser movable into an e'ective position wherein said light beam is intercepted and provided with electrical control means, driving mechanism for said iilm including a driving motor, a belt extendingfrom said driving motor and a reel belt, switches responsive to abnormal conditions in said ilm and motor and reel belts, respectively, a normally closed electric system including said dowser control means, said switches and said motor, and electrical means for causing the extinguishment o said light beam and stopping of said motor uponV the operation of said dowser control means 'by the action of at least one of said switches.

`" 4. In a motion picture machine, the combination with means for establishing a light beam, of a dowser for said light beam comprising a standard having an angle member fulcrumed thereon, one side of said angle member being lighter than the other, and provided with an aperture through which/ the light beam may normally pass, and electromagnetic trip mechanism adapted normally to hold said angle member in a non-intercepting position. I

5. In a motion picture machine having a plurality of moving parts, a light circuit for forming a beam of light, a motor circuit, means movable into an effective position wherein said light beam is intercepted, a switch circuit including means for Opening said switch circuit upon the inoperation of at least one of said moving parts, a plurality of electro-magnetic means which are de-energized by the opening of said switch circuit, one of said electro-magnetic means causing said movable means to be moved into its effective position to intercept the light beam, and the other electro-magnetic means causing an auxiliary electro-magnetic means to be de-energized whereby an additional means is caused to open said light circuit and said motor circuit.

6. In a motion picture machine, a light circuit for forming a beam of light to co-act with a film, operating mechanism for said film including a motor, and al motor circuit, a dowser movable into an effective position wherein said light beam is intercepted, a

. switch circuit adapted to be broken upon the occurrence of a predetermined condition of said operating mechanism, and a pair of relays which are de-energized by the breaking of said switch circuit, one of said relays causing said dowser to move into its effective position, the other of said relays causing an auxiliary relay circuit to break whereby a switch is caused to open said light circuit and said motor circuit.

7. In a motion picture machine, alight circuit for forming a beam of light to co-act with a film, operating mechanism for said film including a motor circuit, a motor and reels, belts interconnecting said motor and reels, a dowser movable into an effective position wherein said light beam is intercepted, a switch circuit adapted to be opened upon the breaking of the film or the interconnecting belts, and a pair of relays which are deenergized by the opening of said switch circuit, one of said relays causing a trip mechanism to move said owser into its effective position, the other of said relays causing an auxiliary relay circuit to be broken whereby an electro-magnetic switch is caused to open said light circuit and said motor circuit.

8. In a motion picture machine, the combination of a light circuit for forming a beam of light to co-act with a film, operating mechanism for moving said film relative to said beam of light including a motor circuit, a motor and reels, belts interconnecting said motor and reels, a dowser movable by a trip mechanism into an eective position wherein said light beam is intercepted, a switch circuit including a plurality of switches, and a pair of relays and a low voltage transformer winding for energizing said relays, said switches adapted to open the switch circuit upon the bre of the ilm or the belts whereby said relays are de-energized, one of said relays causing the trip mechanism to move the dowser into its effective position to intercept the light beam and the other of said relays causing an auxiliary relay circuit to be broken whereby an electro-magnetic switch is caused to open said light circuit and said motor circuit.

9. A dowser for a motion picture machine comprising a pivoted member having a plate section provided with an aperture through which the light beam may pass, a second late section disposed at an angle to said rstmentioned section adapted to intercept said light beam when moved into the position normally occupied by said first-mentioned section, one of said sections being counterweighted, and trip mechanism for permitting the movement of said member only under desired conditions.

10. In a mechanism for projecting a film upon a screen, a motor for passing a film before an arc, a switch connected in series with said motor and adapted to operatively connect it with a source of current, a relay and a circuit for the electric arc controlled by said relay, and means operatively responsive to the Jfailure of said source of current to effeet de-energiiation of said relay, said arc circuit being broken upon the de-energization of said relay.

11. In a motion picture projecting machine having an electriccircuit for supplying current to an arc lamp, a motor circuit an auxiliary circuit, a switch -in the arc circuit, a relay in the auxiliary circuit for closing said switch when the auxiliary circuit is closed and for opening the arc circuit when the auxiliary circuit is opened, and means energized from said motor circuit for closing and opening said auxiliary circuit.

' HARRY HOFFMAN.

PAUL F. KARST. 

